Process of producing high-strength artificial silk by the funnel stretch-spinning process



Jan. 27, 1942-.

a. VON wYss ETAL 2,271,357 PROCESS OF PRODUCING HIGH-STRENGTH ARTIFICIAL SILK BY THE "FUNNEL' STRETCH-SPINNING PROCESS Filed May 28, 1940 0o mm lo m I Wig WW JVOCL I 0. u 6M4 w eaes f F e rm H: GR CD It I? M A 2 1 f 1 a Passed Jan. 27, .1942

UNITED sTATEs PATENT FFICE azuss'z raoca'ss or raonncme men-sworn ARTIFICIAL SILK BY srnaron-srnmme moonss Georg yon Wyss, Gonanor-Buccione, and Ferdinando Biifi and Piero Franchetti, Gozzano, Italy, and Erich Sellner and Alexander Lucittenberg, Wuppertai-Barmen, Germany, assi on: to American Bemberg Corporation,

gn- New York, N. Y., a co poration of Delaware Applicagrn May 28, 1940, Serial No. 337,722

Germany January 9, 1939 silk from cuprammonium cellulose solutions by the funnel stretch-spinning process.

It is an object of the invention to provide means for practising the aforesaid method and comprising agencies and combinations thereof for chemically treating, washing, and spooling the silk produced.

To this end the invention contemplates the use of a series of steps and an apparatus layout whereby the silk as produced in the spinning device in the form of single threads, fibres, or obtained by combining these into bundles strands. skeins or other groups, is subjected to stretching, to treatment adapted to remove copper, and to washing, after which it is spooled on special spooling devices adapted to permitafter-treatment of the thus produced high strength yarn.

It is a further object of the invention to provide a novel spooling device for receiving the high strength yarn produced by the aforesaid method, said device being adapted to be used with the apparatus layout herein recited for practising the present invention and also adapted for use separately therefrom in other silk after-treating processes.

(e. g. especially in the viscose industry) has been entirely eliminated for well known reasons.

Cuprammonium yarns made by the stretchspinning process can also be produced by the pot-spinning process and the latter would always be preferred if it were not for the fact that the sensitive machines used are attacked by the copper-laden sulphuric acid to a far greater extent than in other cases. In accordance with the present inventionhowever an improved silk spooling method is provided which is used conjointly with The accompanying drawing illustrates an'executional example of apparatus adapted for practising the invention.

Fig. 1 shows the apparatus with the spinning funnels, guide rollers, treating rollers, and spooling device in diagrammatic form. m

Fig. 2 is a detailed view in section of the improved spool used in cooperation with the apparatus of Fig. 1. r

Fig. 3 is an end view. of the spool.

In producing artificial silk from cuprammo- 'nium cellulose solutions by means of the funnel stretch-spinning process, the device used for spooling or receiving the spun thread heretofore has usually consisted either of a spool or reel or a centrifuge. The use of a spool or reel is attended by certain drawbacks which manifest themselves during the positioning of the layers as they are applied thereto, thus producing-irregularities in the threads under certain circumstances and inviting the danger of damaging the skeins, etc. when they are later withdrawn from said'spool or reel. Moreover, the primary spun material thus produced is obtained in-the form of skeins or strands and these must be aftertreated in various ways for which purpose they must be in loosened condition; such procedure in an improved silk treating process. This spooling method and especially the device used therefor 'has been but little employed in connection with silk made by the funnel stretch-spinning process but it has been found possible in accordance with the present invention to develop a special embodiment and improvement of said method which is adapted to make it possible to apply it to the production of high strength silk. In accordance with the invention the entire amount of thread, fibre, filament or the like can be produced as an individual member with the aid of a single funnel, or it may be made up of a plurality of strands of thread coming from separatesmall individual funnels, the said strands in that case being assembled together and stretched as a combined thread by means involving the use of rotating stretching members such as Godet rollers. These latter are adapted to rotate at progressively increasing peripheral speeds; at the end of said stretching procedure the thread is passed over another member, say the second roller of a pair of stretching rollers and treated with acid for eliminating the copper contained in the thread. This method however is not limited to the method of execution just described and which involves stretching and deacidification. In fact, the thread may be treated with chemicals while upon or between the rollers or other stretching devices used and either prior to, during, or after the stretching. Thus, the thread may betreated with salt solutions while still on the stretching devices and with ammonia water after being acidified.

. The thread thus stretched and freed from copper certain of the artificial silk industry branches then be wound in the wellknown manner upon the reel or spool in cross-wound fashion and can at the same time or subsequently be treated with a finishing liquid, (oil, size, etc.). The reel or spool may be constituted as a collapsible, perforated cylindrical spool having sheet metal walls. An embodiment of an improved spool of this kind and constituting a feature and object of the present invention is described below in detail and shown in the drawing. The spun thread can be subjected while thereon to any desired aftertreatment (if desired) as by spraying, or forcing the liquid through by either suction or pressure. A spun material so produced is so uniform in nature that it is practically free from dye differ:

ences.

If, while operating within the scope of the process, the thread or fibre structure considered as a whole is made up of a plurality of individual strands or bundles of thread coming from small individualfunnels, certain difiiculties are apt to be encountered; when the usual direction removing either or both of the end flanges I5, ll

axially towards or away from each other by screw operated or other means indicated by the screw 24, thus causing the ends of the cylindrical jacketto ride upon the inclined internal portions 26,

21 of the end flange members l5, l6. This spool can also be converted into a rigid spool by immobilizing the jacket with respect to the two lateral or end flanges I5 and 16 instead of perversing (traverse) rods are used beneath the funnel since the various partial or component thread strands or bundles become traversed to a varying extent by said traverse rod or rods. It has however been found that these non-uniform mechanical strains which give rise to irregularities in dye affinity'and tension conditions in the thread structure as a whole, can be eliminated ifa..common, positively driven traversing roller is substituted for the said traverse rod; said roller may extend over the entire machine or machine sections in a manner similar to that used for the stretching and washing rollers.

The method above described'has been found to be particularly suitable for producing very fine, and in fact the finest titers of high-strength artificial silk.

The mechanism of the process may readily be explained by means of an illustrative apparatus such as that shown in the accompanying drawing. Referring to said drawing, Fig. l, the individual strands or bundles of thread 4, 5, and

6 coming from the spinning funnels l, 2 and 3 are led beneath the positively driven traverse roller I; in addition to causing a change of direction this roller also serves to remove the greater portion of the spinning water from the threads. The combined thread which is kept in taut contact with the roller 1, before being acidified and while still in alkaline condition, then passes over the first roller 8 of a stretch-spinning arrangement and then over the second stretch roller 9 of said arrangement, the latter roller rotating at a higher peripheral speed; in this case also the thread is in taut contact therewith. On this roller, the thread is acidified with diluted sulphuric acid and freed from copper. Thereupon, while still maintaining taut contact with said roller and while under tension it passes to the washing roller I0 upon which it is thoroughly deacidifled and washed out, whence it is then passed through agency of a second traverse roller II to the winding reel or spool l2.

The winding, collapsible spool I2 is one of the features of the invention and rls shown in greater detail in Figs. 2 and 3. The jacket or cylinder mitting the jacket toexpand 'or contract. In that case, the edges l1 and 18 of the cylindrical jacket, which may be suitably beaded, are caused to engage into annular grooves l9 and 20 provided in the two flanges 15, I6 as shown in Fig. 2. A shaft 23 is carried in the central apertures 2| and 22 of the two lateral cover flanges It, IS. The shaft 23 may carry a gear wheel 25 or pulley which serves to drive the spool.

Modifications of the 'present'invention will readily be recognizedv by those skilled in the art, and it is desired to cover all-modifications and variations thereof coming within the scope of the. appended claims. I

What is claimed is:

1. In a method of producing high strength artificial silk from cuprammonium cellulose solution, the steps comprising spinning a plurality of strands of cuprammonium cellulose by the cellulose stretch-spinning process in separated funnels which are adjacent to each other and pointed in the same direction, combining the strands thus spun into a single thread on a positively driven traverse roller-below the funnels,

continuing the stretching and formin of the combined thread by passing the same over a series of positively driven stretching rollers having progressively increasing peripheral speeds and treating the spun thread with washing solutions while on certain rollers of the series, and then spooling the thread upon a perfdratedcylinder. l

2. In a method of producing highi strength artificial silk from cuprammonium cellulose solution, the steps comprising spinning a plurality of strands of cuprammonium cellulose by the cellulose. stretch-spinning process in separated funnels which are adjacent to each other and pointed in the same direction, combining the strands thus spun'into a single thread on a positively driven traverse roller below the funnels, continuing the stretching and forming of the combined thread by passing the same over a series of positively driven guiding rollers having progressively increasing peripheral speeds and during such continued stretching and forming treating the spun thread successively with decoppering and washing agents, and then spooling I3 made of perforated sheet metal is adapted to the thread upon a perforated cylinder.

GEORG VON WYSS. "FERDINANDO BIFFI.

PIERO FRANCHETTI.

ERICH SELLNER.

LUCHI'ENBERG 

